“Thanks to this modernisation, the watertightness testing laboratory has expanded its range of options to test leaks in cars. At the same time, it has doubled its capacity”, says Jaroslav Kasl, head of GQM-3 – Brand Quality Management – Analysis Centre.

 The basic tests include rain simulations. “Usually, the test takes a few dozen minutes, but we also perform long-term tests lasting several hours”, adds team member Jakub Vochvest. The basic “rain” has a water flow of 25 litres/m2/min. However, the test room can also double the downpour to simulate a monsoon.

 After the modernisation, the test room can now also test tilted cars. “This test is one of the latest corporate regulations. We would not be able to do it without the new technology”, continues Petr Kořínek, group coordinator. Tilting the car simulates a situation where, for example, it is parked on a steep incline.

 A pressure washing test is also part of the water test. Pressure washing is carried out by a pressure frame on a carriage, which resembles the equipment from an automatic car wash. This is no coincidence, as the car undergoes these tests during car washes or when it is washed by hand. The pressure in the nozzles ranges between 60 and 90 bar, depending on the test type.

 The local test lab is also developing a new RFID technology (radio frequency identification) to be used by the entire VW Group. It is a non-contact method that uses a digital system to detect the presence of water inside the car. Small RFID sensors responsive to moisture can be integrated into the car’s interior. During the test, a reading frame passes over the car to read the data from the sensors and determine whether it has been exposed to water. 

 If any water is detected, a detailed analysis follows to find out where exactly the water reached (e.g. under the carpets) and why. “In the case of pre-production cars, we are cooperating with the Technical Development department to solve the problem; we fix any defects from serial production mainly with our production colleagues”, Kořínek continues.

 All water used in the watertightness tests is recycled. Ten cubic metres of water drawn from a sump tank circulate in the test room’s closed circuit. “We recycle up to 375 litres per minute and, when running at high speed, up to 1,000 m3 per month”, explains Pavel Novotný, another member of the team. During cleaning, the water passes through coarse and fine filters and is disinfected with UV radiation every night. The water in the circuit is changed once a month and then flows into the sewer.